In May of 1845, Henry David Thoreau started building a cabin out of pitch pines and hickories in a young forest outside Concord, Mass. He went there, as many Americans have read, "to front only the essential facts of life."

Less known is that Thoreau also went there to write. In his two years, two months, and two days spent (in part) on the banks of Walden Pond, the 27-year-old composed his first book, "A Week on the Concord and Merrimack Rivers." The cabin he built, which stood 10-foot square, served as a home and a laboratory for self-reliance. But it was also a writer's studio.

Writers before Thoreau had built similar structures. But the popular success of "Walden" - the chronicle of Thoreau's experiment - fixed in the world's literary consciousness the image of the isolated writer in a spartan shed, extracting poetry from solitude.

Call them cabins, huts, sheds, studies, or studios - the tiny structures have since become icons of the writing life and the unique demands the craft places on those who pursue it. They are normally one room, often unheated, undecorated, appointed only by a desk, a chair, and a window for viewing the world. Some provide beyond the basic creature comforts - modern electricity, plush carpeting, and antique furniture from floor to wall.

Common to all sheds, though, is isolation. Even structures standing no more than 10 feet from the writer's house offer the precious gift of a separate space. A space dedicated solely to writing, even a veritable hovel, is, for some writers, more sympathetic and more necessary than a house, an office building, or a classroom.

"Writers deliberately put themselves in exile by going into a shed," says novelist and historian Jane Smith. "Completing your writing is a way of integrating yourself back into the world."

One school of writers decries comfort. "Appealing workplaces are to be avoided," wrote Annie Dillard in "The Writing Life." "One wants a room with no view, so imagination can meet memory in the dark."

Consider John Cheever's solution. While living in a New York City apartment, the fiction writer would wake up, have breakfast with his wife, take an elevator to the basement, and write all day on a card table facing a blank wall.

"I think the ideal writing room has to be a little uncomfortable - drafty is good," says Ms. Smith.

Other writers accept cushy appointments, or hoist their desks so close to a window that they seem to be writing more outside than in. Fiction writer Amy Hempel's shed on the east end of Long Island is, in the author's words, "almost too cute." The structure is 12-feet long by 9-feet wide, with pinewood floors, cedar shingles, and white paint trim. "It just sort of screams 'writer's studio.' Sometimes I'm self-conscious writing in there."

Proximity to a wood-burning stove is requisite. "It's a handy place for throwing what you wrote that day," says Ms. Hempel. "It's quite satisfying to watch it literally go up in smoke."

A distinguished pedigree of writers has incorporated sheds into their writing life. In 1906, Irish playwright George Bernard Shaw built a hut on a rotating platform that he could move to follow the sun's path across the sky.

Mark Twain's sister-in-law built an octagonal one-room studio for the American humorist when he moved to Elmira, N.Y., in 1874. Twain exalted in the space:

"It is a cozy nest, with just room in it for a sofa and a table and three or four chairs.... And when the storms sweep down the remote valley and the lightning flashes above the hills beyond, and the rain beats upon the roof over my head, imagine the luxury of it!"

Hold my calls

Writing sheds were considered eccentric through most of the 19th century, when the ideal of the writer's workshop was a quiet corner of the home. "At that time, I think, most writers wanted to project an image of being connected to society, as defined by 'home and family,' not solitary artists in their own private 'homes,' " says Stephen Railton, a professor of American literature at the University of Virginia.

Today, individualism and bohemianism largely characterize writers' social identity. Isolation, in turn, is far more acceptable, if not expected. For many writers pressed with domestic distractions, it is also pragmatic.

"I have a theory that women escape from home to write, while men I know escape from the world by staying home to write," says novelist Katharine Weber. "I suspect that this is because the dishes and laundry do not call out their name."

As Virginia Woolf wrote in 1929, "A woman must have money and a room of her own if she is to write fiction." When writer Adrianne Harun felt the squeeze of family life in her 700-square-foot home, her husband found an unorthodox solution: "He chainsawed off an end of the house and converted it into a shed," says Ms. Harun. "The shed is ideal in some ways. It's close enough to home so I can run back and forth for books and deal with things, but I'm not in the midst of phone ringing and the kids," she says.

R.W.B. Lewis's octagonal studio was born from a similar need: "I could see it would be awfully hard to get work done with our first child coming along, but I didn't have anything as imaginative as this in mind as a replacement," says Mr. Lewis. A walkway connects the house with the studio, which sits 30 feet away at the bottom of a shallow ravine. The studio stands on a circle of wooden stilts and a cinder block base. It's lit by a skylight.

For 40 years, the studio has been the crucible of Lewis's writing life, helping him nurse some of his best work - including his Pulitzer Prize-winning biography of Edith Wharton. Lewis still pecks out his work on a tiny typewriter. The technique is old-fashioned, he admits, but not nearly so anachronistic as that of his literary heroine.

"Wharton was a morning worker," says Lewis. "She wrote in bed for years, letting pages fall onto the floor for her maid to run and pick up."

An incentive to get dressed

Unlike Wharton, many writers testify to the necessity of simply getting up and moving. A shed, for some, is more a destination than a surrounding.

"You have to put your pants on in the morning and go someplace," says memoirist Frank Conroy, now director of the University of Iowa's writers' workshop.

The MacDowell Colony in Peterborough, N.H., offers writers tiny studios in which to work for up to eight weeks. "Writers constantly tell us that the walk to their studio through nature proves invaluable to their creative process," says resident manager David Macy.

Leaving the house and heading for the studio, some writers say, is no easier than rolling out of bed and hopping into a cold shower. Many, as a result, detest their shed, even as they admit they would cease to function as human beings without it.

Will Campbell of Mt. Juliet, Tenn., is an exception. The fiction writer built his cabin in 1963 out of logs he obtained by trading a horse. Most everything inside the cabin has sentimental value, from a sitting chair he carved out of a walnut tree, to a plate with an engraving of his boyhood church in Mississippi.

Over the years, the cabin has evolved into a meeting place for friends and readers. A big-hearted man with a Southern drawl, Mr. Campbell once trained for the ministry. His writing on the experience attracts men and women facing spiritual crises of their own.

The meetings in his cabin, which often last into the morning hours, have interrupted his efforts to write his way out of the first writer's block of his career, but he accepts visitors regardless. "I try to discourage people. They think I know more than I do," says Campbell. "But I sort of run an open shop, don't turn folks away. I can get out of work and pretend I'm helping someone."